Does anyone seriously imagine that Sikhs are allowed to fly whilst wearing their ceremonial daggers? If wearing it 'at all times' were so fundamental to their religion, one would never see a Sikh in an aircraft. The rule is flexible enough, it seems, to allow removal of the object for reasons of public well-being.
For Sikhs to protest that Sikh boys are not being allowed to take their knives to school, and that this violates their religion, ignores the fact that teenage boys of whatever faith are testosterone-charged little lumps of gelignite in company, and knives present the same public well-being argument as they do in aircraft.
What next, the Ton Ton Macoute insisting on taking their machetes into Tesco?